M1 PPT

53問 • 9ヶ月前

問題一覧

- may be defined as the ability of the film screen combination to record each point in the object as point on the film. - It is used to describe the visibility of diagnostically important detail in radiograph.

Image Quality

The image quality is influenced by many 5 parameters; CDNSR

contrast, density, noise, sharpness and resolution.

refers to the difference between adjacent areas in the radiograph. It is mainly made up of SUBJECT CONTRAST, FILM CONTRAST, and FOG and SCATTER.

Contrast

the difference in x-ray intensities transmitted through different part of the patient.

Subject contrast

Subject contrast is affected by? IAD

It is affected by the - incident photon energy, - atomic number - density of absorbers.

The fog & scatter will produce unwanted film density which lowers

radiographic contrast.

refers to the density changes caused by the type of film used, how it was exposed, and how it was processed.

Film contrast

Other name of film contrast

Detector contrast

The final set of criteria concerns the film and the usage of

fluorescent displays.

A ________ can provide images with greater clarity than a coarse-grain film.

fine-grain film

The _________ of the radiation influences the perceived graininess.

wavelength

As the wavelength shortens and penetration rises, the film's perceived graininess increases or decreases?

Increases

In addition, higher film development will make the radiograph appear?

Grainier

Radiographs with notable density changes (black to white) show high radiographic contrast.

High contrast

Radiographic pictures with poor radiographic contrast show a minimal density difference between neighboring areas (black to grey).

Low contrast

- The amount of blackness in the radiography picture represents its density. - It is known as "transmitted density" - measures the amount of light that passes through the film

DENSITY

In digital photography, it refers to the movement of the histogram to lower grey levels.

Density

When the ___ increases, the number and energy of x-ray photons generated at the anode increase

kVp

higher number of photons with higher energies reaching the receptor leads to an overall increase in the density of the radiographic image at a larger scale when increasing __ or exposure time.

It alters fil density of the image and therefore affects contrast.

mAs

Higher ___ increases the energy of X-rays, leading to greater penetration and increased density.

kVp

alters the intensity of the beam reaching the image receptor according to the inverse square law.

SID

In traditional radiography, ___ is exposed to radiation passing through the patient and the screen (a phosphorescent material that emits light when exposed to radiation). The ____ _____exposes the film, which is then developed to produce an image.

- Film - Emitted light

refers to the ability of the system to distinguish between small details and structures within the image.

Resolution

ability to image two separate objects and visually distinguish one from the other.

Spatial Resolution resolution

ability to image small structures that have high subject contrast such as bone-soft tissue interface.

Spatial Resolution

ability to distinguish structures with similar subject contrast such as liver-spleen, fat-muscle.

Contrast resolution

- can cause the image quality to deteriorate. - is an artifact that impairs image sharpness and clarity,

Mottle

primarily caused by quantum noise or photon scatter during the exposure process, resulting in an uneven distribution of light or radiation on the film.

Mottle

4 KEY FACTORS CONTRIBUTING TO MOTTLE ILSF

- Insufficient Radiation Exposure - Low Sensitivity Films - Screen Phosphor Characteristics - Film Screen Mismatch

Films with lower sensitivity (low-speed films) require more or less radiation to produce an image?

X-rays are produced at the ____ ____

Focal spot

- area on the anode of the x-ray tube that is hit with electrons from the filament. - All x-ray photons in a beam originate from this

Focal spot

- refers to the distribution in size and space of the silver halide grains in the film emulsion - Similar to structure mottle that refers to the size and shape of the phosphors in the IS.

Film graininess

Similar to photographic film, 400 ASA film is ___ graininess than 100 ASA film. More or less

A primary cause in digital and screen-film radiography, it occurs when too few X-ray photons reach the image receptor, leading to a SPECKLED APPEARANCE. This is common with LOW EXPOSURE LEVELS.

Quantum Mottle

3 Cause of Graininess QFD

1. Quantum Mottle 2. Film Grain 3. Digital Noise

Under film grain, In traditional film radiography, the size and distribution of silver halide grains in the film affect the image smoothness. Larger grains contribute to a what appearance?

Grainier appearance

Under digital noise, In digital radiography, ELECTRONIC INTERFERENCE, LOW SIGNAL LEVELS, or IMAGE PROCESSING can introduce what?

grainy textures

4 FACTORS AFFECTING GRAININESS MKRI

- mAs - kVp - Receptor Sensitivity - Image Processing

Increasing mAs can reduce _____ _____ by providing more photons to the receptor.

quantum mottle

Higher kVp increases penetration but excessive levels may reduce ______, indirectly affecting perceived graininess.

Contrast

Under Image Processing, Poor algorithm settings in digital systems can Introduce

artificial graininess.

Under Receptor Sensitivity, ______ _____ with high sensitivity (high DQE) can capture more details with less nolse. Scatter Radiation - Excessive scatter reduces ______ ____ and can contribute to a mottled appearance.

- Digital detectors - image contrast

4 WAYS FOR REDUCING GRAININESS IUMU

- Increase mAs to ensure sufficient photon count - Use higher DQE detectors - Minimize scatter radiation using proper collimation and grids - Use adequate exposure techniques

If the focal spot area is smaller, the image will be spread out less and will appear ____ on the radiograph. An image formed with a small focal spot will display better ________ ______ because the photons originate from a smaller area. As the focal spot size increases, the area of unsharpness _______ (increase or decrease)

- Sharper - Recorded detail - Increase

produces better recorded detail and spatial resolution

Small focal spot

The focal spot size does not change the _____ of photons in the beam or the _____ of those photons. That means that it does not affect IR exposure or _____.

- Quantity - Quality - Contrast

The focal spot size does not change the orientation of the tube, patient and receptor, so it does not affect size or shape distortion. Because the focal spot size does not affect quality or quantity of the beam, this also means it does not affect ____ ____

patient dose

• The ONLY thing focal spot size affects is

recorded detail

- primary controlling factor of spatial resolution - affects is recorded detail.

Focal Spot Size

does not affect IR exposure because it does not change the number of photons produced or their transmission through the body part.

Focal spot size

Focal spot size does not affect _____ ______ because it does not change the penetrability of the beam or the production of scatter

Image contrast

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RPC M3

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問題一覧

Image Quality

The image quality is influenced by many 5 parameters; CDNSR

contrast, density, noise, sharpness and resolution.

refers to the difference between adjacent areas in the radiograph. It is mainly made up of SUBJECT CONTRAST, FILM CONTRAST, and FOG and SCATTER.

Contrast

the difference in x-ray intensities transmitted through different part of the patient.

Subject contrast

Subject contrast is affected by? IAD

It is affected by the - incident photon energy, - atomic number - density of absorbers.

The fog & scatter will produce unwanted film density which lowers

radiographic contrast.

refers to the density changes caused by the type of film used, how it was exposed, and how it was processed.

Film contrast

Other name of film contrast

Detector contrast

The final set of criteria concerns the film and the usage of

fluorescent displays.

A ________ can provide images with greater clarity than a coarse-grain film.

fine-grain film

The _________ of the radiation influences the perceived graininess.

wavelength

As the wavelength shortens and penetration rises, the film's perceived graininess increases or decreases?

Increases

In addition, higher film development will make the radiograph appear?

Grainier

Radiographs with notable density changes (black to white) show high radiographic contrast.

High contrast

Radiographic pictures with poor radiographic contrast show a minimal density difference between neighboring areas (black to grey).

Low contrast

- The amount of blackness in the radiography picture represents its density. - It is known as "transmitted density" - measures the amount of light that passes through the film

DENSITY

In digital photography, it refers to the movement of the histogram to lower grey levels.

Density

When the ___ increases, the number and energy of x-ray photons generated at the anode increase

kVp

higher number of photons with higher energies reaching the receptor leads to an overall increase in the density of the radiographic image at a larger scale when increasing __ or exposure time.

It alters fil density of the image and therefore affects contrast.

mAs

Higher ___ increases the energy of X-rays, leading to greater penetration and increased density.

kVp

alters the intensity of the beam reaching the image receptor according to the inverse square law.

SID

- Film - Emitted light

refers to the ability of the system to distinguish between small details and structures within the image.

Resolution

ability to image two separate objects and visually distinguish one from the other.

Spatial Resolution resolution

ability to image small structures that have high subject contrast such as bone-soft tissue interface.

Spatial Resolution

ability to distinguish structures with similar subject contrast such as liver-spleen, fat-muscle.

Contrast resolution

- can cause the image quality to deteriorate. - is an artifact that impairs image sharpness and clarity,

Mottle

primarily caused by quantum noise or photon scatter during the exposure process, resulting in an uneven distribution of light or radiation on the film.

Mottle

4 KEY FACTORS CONTRIBUTING TO MOTTLE ILSF

- Insufficient Radiation Exposure - Low Sensitivity Films - Screen Phosphor Characteristics - Film Screen Mismatch

Films with lower sensitivity (low-speed films) require more or less radiation to produce an image?

X-rays are produced at the ____ ____

Focal spot

- area on the anode of the x-ray tube that is hit with electrons from the filament. - All x-ray photons in a beam originate from this

Focal spot

- refers to the distribution in size and space of the silver halide grains in the film emulsion - Similar to structure mottle that refers to the size and shape of the phosphors in the IS.

Film graininess

Similar to photographic film, 400 ASA film is ___ graininess than 100 ASA film. More or less

A primary cause in digital and screen-film radiography, it occurs when too few X-ray photons reach the image receptor, leading to a SPECKLED APPEARANCE. This is common with LOW EXPOSURE LEVELS.

Quantum Mottle

3 Cause of Graininess QFD

1. Quantum Mottle 2. Film Grain 3. Digital Noise

Under film grain, In traditional film radiography, the size and distribution of silver halide grains in the film affect the image smoothness. Larger grains contribute to a what appearance?

Grainier appearance

Under digital noise, In digital radiography, ELECTRONIC INTERFERENCE, LOW SIGNAL LEVELS, or IMAGE PROCESSING can introduce what?

grainy textures

4 FACTORS AFFECTING GRAININESS MKRI

- mAs - kVp - Receptor Sensitivity - Image Processing

Increasing mAs can reduce _____ _____ by providing more photons to the receptor.

quantum mottle

Higher kVp increases penetration but excessive levels may reduce ______, indirectly affecting perceived graininess.

Contrast

Under Image Processing, Poor algorithm settings in digital systems can Introduce

artificial graininess.

- Digital detectors - image contrast

4 WAYS FOR REDUCING GRAININESS IUMU

- Increase mAs to ensure sufficient photon count - Use higher DQE detectors - Minimize scatter radiation using proper collimation and grids - Use adequate exposure techniques

- Sharper - Recorded detail - Increase

produces better recorded detail and spatial resolution

Small focal spot

The focal spot size does not change the _____ of photons in the beam or the _____ of those photons. That means that it does not affect IR exposure or _____.

- Quantity - Quality - Contrast

patient dose

• The ONLY thing focal spot size affects is

recorded detail

- primary controlling factor of spatial resolution - affects is recorded detail.

Focal Spot Size

does not affect IR exposure because it does not change the number of photons produced or their transmission through the body part.

Focal spot size

Focal spot size does not affect _____ ______ because it does not change the penetrability of the beam or the production of scatter

Image contrast